Displaying publications 1 - 20 of 54 in total

  1. Gumel AB, Kubota K, Twizell EH
    Math Biosci, 1998 Aug 15;152(1):87-103.
    PMID: 9727298
    A sequential algorithm is developed for the non-linear dual-sorption model developed by Chandrasekaran et al. [1,2] which monitors pharmacokinetic profiles in percutaneous drug absorption. In the experimental study of percutaneous absorption, it is often observed that the lag-time decreases with the increase in the donor concentration when two or more donor concentrations of the same compound are used. The dual-sorption model has sometimes been employed to explain such experimental results. In this paper, it is shown that another feature observed after vehicle removal may also characterize the dual-sorption model. Soon after vehicle removal, the plots of the drug flux versus time become straight lines on a semilogarithmic scale as in the linear model, but the half-life is prolonged thereafter when the dual-sorption model prevails. The initial half-life after vehicle removal with a low donor concentration is longer than that with a higher donor concentration. These features, if observed in experiments, may be used as evidence to confirm that the dual-sorption model gives an explanation to the non-linear kinetic behaviour of a permeant.
    Matched MeSH terms: Skin Absorption/drug effects*
  2. Sheshala R, Anuar NK, Abu Samah NH, Wong TW
    AAPS PharmSciTech, 2019 Apr 15;20(5):164.
    PMID: 30993407 DOI: 10.1208/s12249-019-1362-7
    This review highlights in vitro drug dissolution/permeation methods available for topical and transdermal nanocarriers that have been designed to modulate the propensity of drug release, drug penetration into skin, and permeation into systemic circulation. Presently, a few of USFDA-approved in vitro dissolution/permeation methods are available for skin product testing with no specific application to nanocarriers. Researchers are largely utilizing the in-house dissolution/permeation testing methods of nanocarriers. These drug release and permeation methods are pending to be standardized. Their biorelevance with reference to in vivo plasma concentration-time profiles requires further exploration to enable translation of in vitro data for in vivo or clinical performance prediction.
    Matched MeSH terms: Skin Absorption*
  3. Sengupta P, Chatterjee B
    Int J Pharm, 2017 Jun 30;526(1-2):353-365.
    PMID: 28461261 DOI: 10.1016/j.ijpharm.2017.04.068
    The Nanoemulgel drug delivery system is a formulation related intervention to improve the systemic delivery and therapeutic profile of lipophilic drugs. Nanoemulgel is an amalgamated formulation of two different systems in which nanoemulsion containing drug is incorporated into a gel base. The fusion of the two systems makes this formulation advantageous in several ways. Lipophilic drugs can be easily incorporated and the skin permeability of the incorporated drugs can be enhanced in several folds due to the finely distributed droplets of nanoemulsion phase. As a result, the pharmacokinetic and pharmacodynamic profiles of the lipophilic drugs are improved significantly. An increasing trend in topical nanoemulgel use in recent years has been noticed because of the better acceptability of the preparation to the patients due to their noninvasive delivery, avoidance of gastrointestinal side effects, easier applicability and good therapeutic and safety profile. Despite of having few limitations, nanoemulgel formulation can be considered as a potential and promising candidates for topical delivery of lipophilic drugs in the future. The aim of this review is to evaluate and report the current potential and future scope of nanoemulgel formulation for becoming an effective delivery system for poorly water soluble drugs. In this review, we have summarized and discussed the outcome of different studies on permeability, pharmacokinetic, pharmacodynamic and safety profile of the drugs delivered topically through nanoemulgel. Rationality of use along with the major challenges to overcome for nanoemulgel formulation has been discussed.
    Matched MeSH terms: Skin Absorption*
  4. Singh I, Nair RS, Gan S, Cheong V, Morris A
    Pharm Dev Technol, 2019 Apr;24(4):448-454.
    PMID: 30084268 DOI: 10.1080/10837450.2018.1509347
    The drawbacks associated with chemical skin permeation enhancers such as skin irritation and toxicity necessitated the research to focus on potential permeation enhancers with a perceived lower toxicity. Crude palm oil (CPO) is obtained by direct compression of the mesocarp of the fruit of the oil palm belonging to the genus Elaeis. In this research, CPO and tocotrienol-rich fraction (TRF) of palm oil were evaluated for the first time as skin permeation enhancers using full-thickness human skin. The in vitro permeation experiments were conducted using excised human skin mounted in static upright 'Franz-type' diffusion cells. The drugs selected to evaluate the enhancing effects of these palm oil derivatives were 5-fluorouracil, lidocaine and ibuprofen: compounds covering a wide range of Log p values. It was demonstrated that CPO and TRF were capable of enhancing the percutaneous permeation of drugs across full-thickness human skin in vitro. Both TRF and CPO were shown to significantly enhance the permeation of ibuprofen with flux values of 30.6 µg/cm2 h and 23.0 µg/cm2 h respectively, compared to the control with a flux of 16.2 µg/cm2 h. The outcome of this research opens further scope for investigation on the transdermal penetration enhancement activity of pure compounds derived from palm oil.
    Matched MeSH terms: Skin Absorption/drug effects*; Skin Absorption/physiology
  5. Khan NR, Harun MS, Nawaz A, Harjoh N, Wong TW
    Curr Pharm Des, 2015;21(20):2848-66.
    PMID: 25925113
    Transdermal drug delivery is impeded by the natural barrier of epidermis namely stratum corneum. This limits the route to transport of drugs with a log octanol-water partition coefficient of 1 to 3, molecular weight of less than 500 Da and melting point of less than 200°C. Nanotechnology has received widespread investigation as nanocarriers are deemed to be able to fluidize the stratum corneum as a function of size, shape, surface charges, and hydrophilicity-hydrophobicity balance, while delivering drugs across the skin barrier. This review provides an overview and update on the latest designs of liposomes, ethosomes, transfersomes, niosomes, magnetosomes, oilin- water nanoemulsions, water-in-oil nanoemulsions, bicontinuous nanoemulsions, covalently crosslinked polysaccharide nanoparticles, ionically crosslinked polysaccharide nanoparticles, polyelectrolyte coacervated nanoparticles and hydrophobically modified polysaccharide nanoparticles with respect to their ability to fuse or fluidize lipid/protein/tight junction regimes of skin, and effect changes in skin permeability and drug flux. Universal relationships of nanocarrier size, zeta potential and chemical composition on transdermal permeation characteristics of drugs will be developed and discussed.
    Matched MeSH terms: Skin Absorption/drug effects; Skin Absorption/physiology*
  6. Harjoh N, Wong TW, Caramella C
    Int J Pharm, 2020 Jun 30;584:119416.
    PMID: 32423875 DOI: 10.1016/j.ijpharm.2020.119416
    Inhaled/oral insulin have been investigated as an alternative to injectable insulin, but are met with unsatisfactory outcomes. Transdermal administration bears several advantages unmet by inhalation/oral delivery, but macromolecular drugs permeation is poor. This study explored microwave to elicit transdermal insulin permeation, and compared against conventional permeation enhancers (fatty acids) in vitro/in vivo. The transdermal insulin permeation was promoted by microwave (2450 MHz/1 mW) > oleic acid (monounsaturated) ~ linoleic acid (double unsaturated bonds). The linolenic acid (triple unsaturated bonds) or combination of microwave/fatty acid reduced skin insulin permeation. Transdermal insulin permeation enhancement was attributed to epidermal lipid bilayer fluidization (CH) and corneocyte shrinkage due to keratin condensation (OH/NH, CO), which had aqueous pore enlarged to facilitate insulin transport. Its reduction by linolenic acid, a molecularly larger and rigid fatty acid with higher surface tension, was due to reduced fatty acid permeation into epidermis and minimal skin microstructural changes. The oleic acid, despite favoured skin microstructural changes, did not provide a remarkably high insulin permeation due to it embedded in skin as hydrophobic shield to insulin transport. Microwave penetrates skin volumetrically with no chemical residue retention. It alone promoted insulin absorption and sustained blood glucose level reduction in vivo.
    Matched MeSH terms: Skin Absorption/drug effects; Skin Absorption/physiology*; Skin Absorption/radiation effects
  7. Goh CF, Hadgraft J, Lane ME
    Int J Pharm, 2022 Feb 25;614:121447.
    PMID: 34998922 DOI: 10.1016/j.ijpharm.2021.121447
    For effective topical and transdermal drug delivery, it is necessary for most actives to penetrate and permeate through the stratum corneum (SC). Extensive investigation of the thermal behaviour of mammalian SC has been performed to understand the barrier function of the skin. However, little attention has been paid to the related experimental variables in thermal analysis of the SC using differential scanning calorimetry that may influence the results obtained from such studies. In this review, we provide a comprehensive overview of the thermal transitions of the SC of both porcine and human skin. More importantly, the selection and impact of the experimental and instrumental parameters used in thermal analysis of the SC are critically evaluated. New opportunities for the use of thermal analysis of mammalian SC in advancing skin research, particularly for elucidation of the actions of excipients employed in topical and transdermal formulations on the skin are also highlighted.
    Matched MeSH terms: Skin Absorption
  8. Ngan CL, Basri M, Tripathy M, Abedi Karjiban R, Abdul-Malek E
    ScientificWorldJournal, 2014;2014:219035.
    PMID: 25165736 DOI: 10.1155/2014/219035
    Fullerene nanoemulsions were formulated in palm kernel oil esters stabilized by low amount of mixed nonionic surfactants. Pseudoternary phase diagrams were established in the colloidal system of PKOEs/Tween 80 : Span 80/water incorporated with fullerene as antioxidant. Preformulation was subjected to combination of high and low energy emulsification methods and the physicochemical characteristics of fullerene nanoemulsions were analyzed using electroacoustic spectrometer. Oil-in-water (O/W) nanoemulsions with particle sizes in the range of 70-160 nm were formed. The rheological characteristics of colloidal systems exhibited shear thinning behavior which fitted well into the power law model. The effect of xanthan gum (0.2-1.0%, w/w) and beeswax (1-3%, w/w) in the estimation of thermodynamics was further studied. From the energetic parameters calculated for the viscous flow, a moderate energy barrier for transport process was observed. Thermodynamic study showed that the enthalpy was positive in all xanthan gum and beeswax concentrations indicating that the formation of nanoemulsions could be endothermic in nature. Fullerene nanoemulsions with 0.6% or higher xanthan gum content were found to be stable against creaming and flocculation when exposed to extreme environmental conditions.
    Matched MeSH terms: Skin Absorption/physiology*
  9. Ng SF, Rouse JJ, Sanderson FD, Meidan V, Eccleston GM
    AAPS PharmSciTech, 2010 Sep;11(3):1432-41.
    PMID: 20842539 DOI: 10.1208/s12249-010-9522-9
    Over the years, in vitro Franz diffusion experiments have evolved into one of the most important methods for researching transdermal drug administration. Unfortunately, this type of testing often yields permeation data that suffer from poor reproducibility. Moreover, this feature frequently occurs when synthetic membranes are used as barriers, in which case biological tissue-associated variability has been removed as an artefact of total variation. The objective of the current study was to evaluate the influence of a full-validation protocol on the performance of a tailor-made array of Franz diffusion cells (GlaxoSmithKline, Harlow, UK) available in our laboratory. To this end, ibuprofen was used as a model hydrophobic drug while synthetic membranes were used as barriers. The parameters investigated included Franz cell dimensions, stirring conditions, membrane type, membrane treatment, temperature regulation and sampling frequency. It was determined that validation dramatically reduced derived data variability as the coefficient of variation for steady-state ibuprofen permeation from a gel formulation was reduced from 25.7% to 5.3% (n = 6). Thus, validation and refinement of the protocol combined with improved operator training can greatly enhance reproducibility in Franz cell experimentation.
    Matched MeSH terms: Skin Absorption/physiology
  10. Khan NR, Wong TW
    Expert Opin Drug Deliv, 2016 09;13(9):1209-19.
    PMID: 27212391 DOI: 10.1080/17425247.2016.1193152
    OBJECTIVES: Skin drug retention is required in local treatment of skin cancer. This study investigated the interplay effects of ethosomes and microwave in transdermal drug delivery. Skin pre-treatment by microwave and applied with liquified medicine is deemed to 'cement' the skin thereby raising skin drug deposition.

    METHODS: 5-fluorouracil-loaded ethosomes were prepared and subjected to size, zeta potential, morphology, drug content, drug release and skin permeation tests. The molecular characteristics of untreated, microwave and/or ethosome-treated skins were examined by Fourier transform infrared and raman spectroscopy, thermal and electron microscopy techniques.

    RESULTS: The skin drug retention was promoted using larger ethosomes with negative zeta potentials that repelled anionic lipids of skin and hindered vesicle permeation into deep layers. These ethosomes had low ethanol content. They were less able to fluidize the lipid and defluidize the protein domains at epidermis to enlarge aqueous pores for drug permeation. Pre-treatment of skin by 2450 MHz microwave for 2.5 min further increased skin drug penetration and retention of low ethanol ethosomes and provided lower drug permeation than cases treated for 1.15 min and 5 min. A 2.5 min treatment might be accompanied by specific dermal protein fluidization via C=O moiety which translated to macromolecular swelling, narrowing of intercellular spaces at lower skin layers, increased drug retention and reduced drug permeation.

    CONCLUSION: Ethosomes and microwave synergized to promote skin drug retention.

    Matched MeSH terms: Skin Absorption*
  11. Nawaz A, Wong TW
    Carbohydr Polym, 2017 Feb 10;157:906-919.
    PMID: 27988008 DOI: 10.1016/j.carbpol.2016.09.080
    This study investigated transdermal drug delivery mechanisms of chitosan nanoparticles with the synergistic action of microwave in skin modification. Chitosan nanoparticles, with free or conjugated 5-fluorouracil, were prepared by nanospray-drying technique. Their transdermal drug delivery profiles across untreated and microwave-treated skins (2450MHz 5min, 5+5min; 3985MHz 5min) were examined. Both constituent materials of nanoparticles and drug encapsulation were required to succeed transdermal drug delivery. The drug transport was mediated via nanoparticles carrying drug across the skin and/or diffusion of earlier released drug molecules from skin surfaces. The drug/nanoparticles transport was facilitated through constituent nanoparticles and microwave fluidizing protein/lipid domains of epidermis and dermis (OH, NH, CH, CN) and dermal trans-to-gauche lipid conformational changes. The microwave induced marked changes to the skin ceramide content homogeneity. The chitosan nanoparticles largely affected the palmitic acid and keratin domains. Combined microwave and nanotechnologies synergize transdermal drug delivery.
    Matched MeSH terms: Skin Absorption*
  12. Khan NR, Wong TW
    Artif Cells Nanomed Biotechnol, 2018;46(sup1):568-577.
    PMID: 29378453 DOI: 10.1080/21691401.2018.1431650
    This study focuses on the use of ethosome and microwave technologies to facilitate skin penetration and/or deposition of 5-fluorouracil in vitro and in vivo. Low ethanol ethosomes were designed and processed by mechanical dispersion technique and had their size, zeta potential, morphology, drug content and encapsulation efficiency characterized. The skin was pre-treated with microwave at 2450 MHz for 2.5 min with ethosomes applied topically and subjected to in vitro and in vivo skin drug permeation as well as retention evaluation. The drug and/or ethosomes cytotoxicity, uptake and intracellular trafficking by SKMEL-28 melanoma cell culture were evaluated. Pre-treatment of skin by microwave promoted significant drug deposition in skin from ethosomes in vitro while keeping the level of drug permeation unaffected. Similar observations were obtained in vivo with reduced drug permeation into blood. Combination ethosome and microwave technologies enhanced intracellular localization of ethosomes through fluidization of cell membrane lipidic components as well as facilitating endocytosis by means of clathrin, macropinocytosis and in particularly lipid rafts pathways. The synergistic use of microwave and ethosomes opens a new horizon for skin malignant melanoma treatment.
    Matched MeSH terms: Skin Absorption*
  13. Nair RS, Billa N, Leong CO, Morris AP
    Pharm Dev Technol, 2021 Feb;26(2):243-251.
    PMID: 33274672 DOI: 10.1080/10837450.2020.1860087
    Tocotrienol (TRF) ethosomes were developed and evaluated in vitro for potential transdermal delivery against melanoma. The optimised TRF ethosomal size ranged between 64.9 ± 2.2 nm to 79.6 ± 3.9 nm and zeta potential (ZP) between -53.3 mV to -62.0 ± 2.6 mV. Characterisation of the ethosomes by ATR-FTIR indicated the successful formation of TRF-ethosomes. Scanning electron microscopy (SEM) images demonstrated the spherical shape of ethosomes, and the entrapment efficiencies of all the formulations were above 66%. In vitro permeation studies using full-thickness human skin showed that the permeation of gamma-T3 from the TRF ethosomal formulations was significantly higher (p skin (p skin permeation and high cell viability associated with this formulation suggest a promising carrier for transdermal delivery.
    Matched MeSH terms: Skin Absorption*
  14. Rehman K, Zulfakar MH
    Drug Dev Ind Pharm, 2014 Apr;40(4):433-40.
    PMID: 23937582 DOI: 10.3109/03639045.2013.828219
    Transdermal drug delivery systems are a constant source of interest because of the benefits that they afford in overcoming many drawbacks associated with other modes of drug delivery (i.e. oral, intravenous). Because of the impermeable nature of the skin, designing a suitable drug delivery vehicle that penetrates the skin barrier is challenging. Gels are semisolid formulations, which have an external solvent phase, may be hydrophobic or hydrophilic in nature, and are immobilized within the spaces of a three-dimensional network structure. Gels have a broad range of applications in food, cosmetics, biotechnology, pharmatechnology, etc. Typically, gels can be distinguished according to the nature of the liquid phase, for example, organogels (oleogels) contain an organic solvent, and hydrogels contain water. Recent studies have reported other types of gels for dermal drug application, such as proniosomal gels, emulgels, bigels and aerogels. This review aims to introduce the latest trends in transdermal drug delivery via traditional hydrogels and organogels and to provide insight into the latest gel types (proniosomal gels, emulgels, bigels and aerogels) as well as recent technologies for topical and transdermal drug delivery.
    Matched MeSH terms: Skin Absorption*
  15. Rajinikanth PS, Chellian J
    Int J Nanomedicine, 2016 Oct 5;11:5067-5077.
    PMID: 27785014
    The aim of this study was to develop a nanostructured lipid carrier (NLC)-based hydrogel and study its potential for the topical delivery of 5-fluorouracil (5-FU). Precirol(®) ATO 5 (glyceryl palmitostearate) and Labrasol(®) were selected as the solid and liquid lipid phases, respectively. Poloxamer 188 and Solutol(®) HS15 (polyoxyl-15-hydroxystearate) were selected as surfactants. The developed lipid formulations were dispersed in 1% Carbopol(®) 934 (poly[acrylic acid]) gel medium in order to maintain the topical application consistency. The average size, zeta potential, and polydispersity index for the 5-FU-NLC were found to be 208.32±8.21 nm, -21.82±0.40 mV, and 0.352±0.060, respectively. Transmission electron microscopy study revealed that 5-FU-NLC was <200 nm in size, with a spherical shape. In vitro drug permeation studies showed a release pattern with initial burst followed by sustained release, and the rate of 5-FU permeation was significantly improved for 5-FU-NLC gel (10.27±1.82 μg/cm(2)/h) as compared with plain 5-FU gel (2.85±1.12 μg/cm(2)/h). Further, skin retention studies showed a significant retention of 5-FU from the NLC gel (91.256±4.56 μg/cm(2)) as compared with that from the 5-FU plain gel (12.23±3.86 μg/cm(2)) in the rat skin. Skin irritation was also significantly reduced with 5-FU-NLC gel as compared with 5-FU plain gel. These results show that the prepared 5-FU-loaded NLC has high potential to improve the penetration of 5-FU through the stratum corneum, with enormous retention and with minimal skin irritation, which is the prerequisite for topically applied formulations.
    Matched MeSH terms: Skin Absorption/drug effects; Skin Absorption/radiation effects
  16. Noor NM, Khan AA, Hasham R, Talib A, Sarmidi MR, Aziz R, et al.
    IET Nanobiotechnol, 2016 Aug;10(4):195-9.
    PMID: 27463789 DOI: 10.1049/iet-nbt.2015.0041
    Virgin coconut oil (VCO) is the finest grade of coconut oil, rich in phenolic content, antioxidant activity and contains medium chain triglycerides (MCTs). In this work formulation, characterisation and penetration of VCO-solid lipid particles (VCO-SLP) have been studied. VCO-SLP were prepared using ultrasonication of molten stearic acid and VCO in an aqueous solution. The electron microscopy imaging revealed that VCO-SLP were solid and spherical in shape. Ultrasonication was performed at several power intensities which resulted in particle sizes of VCO-SLP ranged from 0.608 ± 0.002 µm to 44.265 ± 1.870 µm. The particle size was directly proportional to the applied power intensity of ultrasonication. The zeta potential values of the particles were from -43.2 ± 0.28 mV to -47.5 ± 0.42 mV showing good stability. The cumulative permeation for the smallest sized VCO-SLP (0.608 µm) was 3.83 ± 0.01 µg/cm(2) whereas for larger carriers it was reduced (3.59 ± 0.02 µg/cm(2)). It is concluded that SLP have the potential to be exploited as a micro/nano scale cosmeceutical carrying vehicle for improved dermal delivery of VCO.
    Matched MeSH terms: Skin Absorption/drug effects; Skin Absorption/physiology
  17. Prasanthi Sri, Senthil Adimoolam, Ahmad Mahmud
    Studies were conducted to assess the percutaneous absorption of the triacyglycerols (TAGs), tocols and carotenoids present in crude and refined palm oil. In vitro experiments using upright Franz diffusion cells were employed to investigate the permeability of these compounds across full thickness human skin and into the receptor solution. Cetrimide, a cationic surfactant was chosen to be used as a solubilising agent in the receptor phase with an optimum concentration of 3.0 mg/mL and was able to provide sink conditions throughout the permeation. TAGs, tocols and carotenoids all permeated human skin from crude palm oil (CPO), whereas only TAGs permeated when refined palm oil (RPO) was used. Of the TAGs, oleic acid-containing TAGs was preferentially absorbed despite palmitic acid being the most prevalent fatty acid (FA) in TAGs. Tocols in the form of α-T3 showed the highest permeation followed by γ-T3, α-T and the lowest permeation was observed for δ-T3. Carotenoids (α-carotene and β-carotene) also showed an appreciable amount of permeation from CPO.
    Matched MeSH terms: Skin Absorption
  18. Pandey M, Choudhury H, Gunasegaran TAP, Nathan SS, Md S, Gorain B, et al.
    Drug Deliv Transl Res, 2019 04;9(2):520-533.
    PMID: 29488170 DOI: 10.1007/s13346-018-0480-1
    Atopic dermatitis (AD) is a chronically relapsing eczematous skin disease characterised by frequent episodes of rashes, severe flares, and inflammation. Till date, there is no absolute therapy for the treatment of AD; however, topical corticosteroids (TCs) are the majorly prescribed class of drugs for the management of AD in both adults and children. Though, topical route is most preferable; however, limited penetration of therapeutics across the startum cornum (SC) is one of the major challenges for scientists. Therefore, the present study was attempted to fabricate a moderate-potency TC, betamethasone valerate (BMV), in the form of chitosan nanoparticles (CS-NPs) for optimum dermal targeting and improved penetration across the SC. To further improve the targeting efficiency of BMV and to potentiate its therapeutic efficacy, the fabricated BMV-CS-NPs were coated with hyaluronic acid (HA). The prepared NPs were characterised for particle size, zeta potential, polydispersity index (PDI), entrapment efficiency, loading capacity, crystallinity, thermal behaviour, morphology, in vitro release kinetics, drug permeation across the SC, and percentage of drug retained into various skin layers. Results showed that optimised HA-BMV-CS-NPs exhibited optimum physicochemical characteristics including finest particle size (skin surface (pH 5.5). Drug permeation efficiency of BMV was comparatively higher in case of BMV-CS-NPs; however, the amount of drug retained into the epidermis and the dermis was comparatively higher in case of HA-BMV-CS-NPs, compared to BMV-CS-NPs. Conclusively, we anticipate that HA-BMV-CS-NPs could be a promising nanodelivery system for efficient dermal targeting of BMV and improved anti-AD efficacy.
    Matched MeSH terms: Skin Absorption
  19. Goh CF, Moffat JG, Craig DQM, Hadgraft J, Lane ME
    Mol Pharm, 2019 01 07;16(1):359-370.
    PMID: 30525649 DOI: 10.1021/acs.molpharmaceut.8b01027
    Drug crystallization on and in the skin has been reported following application of topical or transdermal formulations. This study explored novel probe-based approaches including localized nanothermal analysis (nano-TA) and photothermal microspectroscopy (PTMS) to investigate and locate drug crystals in the stratum corneum (SC) of porcine skin following application of simple ibuprofen (IBU) formulations. We also conducted in vitro skin permeation studies and tape stripping. The detection of drug crystals in the SC on tape strips was confirmed using localized nano-TA, based on the melting temperature of IBU. The melting of IBU was also evident as indicated by a double transition and confirmed the presence of drug crystals in the SC. The single point scans of PTMS on the tape strips allowed collection of the photothermal FTIR spectra of IBU, confirming the existence of drug crystals in the skin. The combined methods also indicated that drug crystallized in the SC at a depth of ∼4-7 μm. Future studies will examine the potential of these techniques to probe crystallization of other commonly used actives in topical and transdermal formulations.
    Matched MeSH terms: Skin Absorption
  20. Mahmood S, Taher M, Mandal UK
    Int J Nanomedicine, 2014;9:4331-46.
    PMID: 25246789 DOI: 10.2147/IJN.S65408
    Raloxifene hydrochloride, a highly effective drug for the treatment of invasive breast cancer and osteoporosis in post-menopausal women, shows poor oral bioavailability of 2%. The aim of this study was to develop, statistically optimize, and characterize raloxifene hydrochloride-loaded transfersomes for transdermal delivery, in order to overcome the poor bioavailability issue with the drug. A response surface methodology experimental design was applied for the optimization of transfersomes, using Box-Behnken experimental design. Phospholipon(®) 90G, sodium deoxycholate, and sonication time, each at three levels, were selected as independent variables, while entrapment efficiency, vesicle size, and transdermal flux were identified as dependent variables. The formulation was characterized by surface morphology and shape, particle size, and zeta potential. Ex vivo transdermal flux was determined using a Hanson diffusion cell assembly, with rat skin as a barrier medium. Transfersomes from the optimized formulation were found to have spherical, unilamellar structures, with a homogeneous distribution and low polydispersity index (0.08). They had a particle size of 134±9 nM, with an entrapment efficiency of 91.00%±4.90%, and transdermal flux of 6.5±1.1 μg/cm(2)/hour. Raloxifene hydrochloride-loaded transfersomes proved significantly superior in terms of amount of drug permeated and deposited in the skin, with enhancement ratios of 6.25±1.50 and 9.25±2.40, respectively, when compared with drug-loaded conventional liposomes, and an ethanolic phosphate buffer saline. Differential scanning calorimetry study revealed a greater change in skin structure, compared with a control sample, during the ex vivo drug diffusion study. Further, confocal laser scanning microscopy proved an enhanced permeation of coumarin-6-loaded transfersomes, to a depth of approximately160 μM, as compared with rigid liposomes. These ex vivo findings proved that a raloxifene hydrochloride-loaded transfersome formulation could be a superior alternative to oral delivery of the drug.
    Matched MeSH terms: Skin Absorption/drug effects*
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